The present invention relates to a data storage system. In particular, the present invention relates to a tribological surface structure for head disc interface.
Disc drives are well known in the industry. Such drives use rigid discs coated with a magnetizable medium for storage of digital information in a plurality of concentric data tracks. Typically, disc drives include a disc pack including a plurality of concentric discs mounted on a spindle motor which causes the discs to spin. Heads (or slider) carrying transducer elements are supported relative to the disc surfaces to read and or write digital information to the disc surfaces.
During or prior to operation the head contacts the disc surface. For proximity recording the head contacts the disc surface for contacts starts and stops (xe2x80x9cCSSxe2x80x9d), and for contact recording the slider or head is dragged across the disc surface for read and write operations. Stiction or friction between contacting interface surfaces of the head and disc is proportional to the normal force on the head, the bearing area and the interfacial material properties of the head and disc interface surfaces: including the combined Modulus of Elasticity, the hardness of the materials, the nominal area of contact, the lubricant properties and surface roughness of the head disc interface surfaces.
For CSS operations, the spindle motor produces torque to overcome stiction and initiate xe2x80x9cspin-upxe2x80x9d. Stiction increases the motor torque required to spin-up the disc drive. If stiction is too large for motor torque to overcome, spin-up failure could occur. High friction and stiction increases power requirements for spin up and operating power requirements for contact or near contact recording. Contact pads or pad assisted landing on CSS heads reduces contact area to reduce stiction. Roughened head-disc interface surfaces reduces stiction and friction. Contact pads and roughened surface structures can increase the spacing required between the head and disc surface or can increase head-disc contact and data loss and damage to the disc drive. The present invention addresses these and other problems.
The present invention relates to a head disc interface having a fine pitch surface roughness including fine pitch projections having a relatively smooth roughness height and a projection pitch  less than 1.0 xcexcm for optimizing tribological performance.